The present invention relates to a method and apparatus for mapping quality of service in one communication network to quality of service in another communication network.
Communication networks are often interconnected so that users of different networks can communicate with one another. The Internet is a familiar example. Many enterprises also have intranets in which a backbone network is linked to a plurality of local area networks, mobile communication networks, and the like.
For many types of communication, a certain quality of service (commonly abbreviated QoS) must be provided. Different networks have different methods of defining and implementing quality of service, so when a communication link passes through several networks, it is not easy to provide an end-to-end QoS guarantee. A conventional method is to use look-up tables, referred to as QoS mapping tables, to translate quality of service in one network to quality of service in another network, but there are certain problems involved in this method.
One problem is that QoS technology is constantly evolving, and new QoS standards or techniques are rarely introduced into all relevant networks simultaneously. Each time the QoS practices in a network are changed, the QoS mapping tables in that network and the networks with which it communicates must be updated. A significant amount of communication bandwidth must be devoted to exchanges of QoS information, just to keep different networks informed of each other""s QoS methods, protocols, parameters, and so on. A particular problem is that QoS information must be provided in advance, before it is actually needed. Network bandwidth is sometimes consumed by exchanges of QoS information that will never be needed.
Another problem is that some of the QoS information in a network tends to change dynamically. It is extremely difficult for a QoS mapping table, which is a collection of essentially static information, to cope with a dynamically changing QoS environment in another network.
Yet another problem is that an end user with special QoS requirements may find that these requirements cannot be met satisfactorily, because of restrictions rigidly embedded in the QoS mapping tables.
An object of the present invention is to provide a QoS mapping method that is timely and efficient.
Another object of the invention is to provide end users with control over QoS mapping.
The invented QoS mapping method comprises the steps of:
generating a program mapping quality of service in a first communication network to quality of service in a second communication network;
transmitting the program from an exit node of the first network to an entry node of the second network in an active packet; and
executing the program at the entry node of the second communication network.
The program may be generated at the exit node of the first communication network, or at an end-user node from which the active packet originates. Alternatively, part of the program, describing basic QoS requirements, may be generated at the end-user node, and another part of the program, describing QoS mapping methods, may be generated at the exit node of the first communication network.
When QoS practices in the second communication network are changed, the entry node of the second communication network may generate another program relating QoS information before and after the change, and this program may be invoked from the program sent by the exit node of the first communication network. Information describing the new QoS practices may also be inserted into an active packet sent from the second communication network to the first communication network.
The invention further provides apparatus for interconnecting the first and second communication networks, employing the invented QoS mapping method.
The invented method and apparatus are timely, because they exchange QoS information at just the times when the information is needed. They are efficient because they do not exchange Qo6 information at other times, and because QoS information can be coded efficiently in program form.
When the program in an active packet is generated partially or entirely at an end-user node, the end user gains control over the QoS mapping methods that will be employed as the active packet travels from one network to another.